Prevalence of herbicide‐resistant weed species in Malaysian rice fields: A review

Abstract

The management of weeds in Malaysian rice fields is very much herbicide-based. The heavy reliance on herbicide for weed control by many rice-growers arguably eventually has led to the development and evolution of herbicide-resistant biotypes in Malaysian rice fields over the years. The continuous use of synthetic auxin (phenoxy group) herbicides and acetohydroxyacid synthase-inhibiting herbicides to control rice weeds was consequential in leading to the emergence and prevalence of resistant weed biotypes. This review discusses the history and confirmed cases and incidence of herbicide-resistant weeds in Malaysian rice fields. It also reviews the Clearfield Production System and its impact on the evolution of herbicide resistance among rice weed species and biotypes. This review also emphasizes the strategies and management options for herbicide-resistant rice field weeds within the framework of herbicide-based integrated weed management. These include the use of optimum tillage practices, certified clean seeds, increased crop competition through high seeding rates, crop rotation, the application of multiple modes of action of herbicides in annual rotations, tank mixtures and sequential applications to enable a broad spectrum of weed control, increase the selective control of noxious weed species in a field and help to delay the resistance evolution by reducing the selection pressure that is forced on those weed populations by a specific herbicidal mode of action.

Call of the wild rice: Oryza rufipogon shapes weedy rice evolution in Southeast Asia

“…comm.). As the cultivation of herbicide‐resistant rice planting has become more popular with Malaysian farmers in the last decade, the problem of herbicide‐tolerant weedy rice has concurrently arisen (Engku et al., ; Ruzmi, Ahmad‐Hamdani, & Bakar, ). This causes additional strain on the rice industry, particularly in regions where herbicide‐tolerant rice cultivation has not been widely adopted.…”

Ser-653-Asn substitution in the acetohydroxyacid synthase gene confers resistance in weedy rice to imidazolinone herbicides in Malaysia

“…Currently, weedy rice represents the eighth herbicide-resistant weed species in Malaysian rice fields [ 9 ] and has been recognized as the most problematic weed in rice growing areas of Malaysia [ 26 ]. Recently, rice growers who have been cultivating IMI-rice for more than eight planting seasons in Selangor, Perak, Pulau Pinang, Kedah, and Perlis states of Malaysia have reported reduced efficacy of IMI herbicides to control weedy rice and other weed species in their fields.…”

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“…Weedy rice also can become a model plant for weed ecological genetic studies to elucidate genetic and evolutionary mechanism of weed adaptation and competitiveness in agro-ecosystems using combinative approaches of ecology, genetics and genomics to provide fundamental knowledge to improve or devise new weedy rice management strategies (Mispan et al 2013;Mispan, 2014). The biotechnology techniques and technologies especially in the metabolomics studies to illuminate useful chemical compounds (Saiman, 2014) can be transferred to weedy rice systems for further understanding on herbicide mechanisms and actions to weedy rice (Ruzmi et al 2017). In addition to physical approaches (Control Gaps 1-5) to reduce the impact of weedy rice in rice production, education and awareness about weedy rice management need to be empowered.…”